25th Amendment: how does it work and could it end Trump's presidency early?

Provision in US Constitution grants vice president or Cabinet authority to remove a sitting US president

As the violence reached a crescendo on Capitol Hill with pro-Trump demonstrators taking to the floor of the US Congress, some legislators called for the 25th amendment to be used to remove President Donald Trump from office before his term expires on January 20.

With the widespread alarm and disbelief at the chaos unfolding in Washington, and many accusing Mr Trump of encouraging the mob, the 25th amendment also started to trend on Twitter.

The 25th amendment to the US Constitution was ratified in 1965. It came to fruition a couple of years after the assassination of John F Kennedy amid some medical concerns surrounding his successor, Lyndon B Johnson. The amendment sought to clarify procedures for the succession of the presidency or vice presidency in the event that the office was vacated for various reasons.

Most of the amendment, in particular, deals with scenarios where a president is unable to discharge the powers and duties of his office due to health reasons.

Those scenarios clearly do not apply to Mr Trump, who is in relatively decent health.

There is, however, section 4 of the amendment, which could be problematic for any sitting president regardless of his or her health.

"Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President."

That section of the amendment basically gives the vice president or Cabinet members the ability to determine a president's ability to execute his or her job.

Even though the 25th amendment sought to clarify and even simplify succession plans, some have argued that this particular section makes removing a president a subjective judgment call.

Media reports shortly following the storming of the Capitol also indicated that some in Mr Trump's Cabinet also contemplated using the rarely discussed amendment.

Could Vice President Mike Pence and members of Mr Trump's Cabinet have made this determination? Of course, any vice president or Cabinet could do so hypothetically. There's the fine print of the amendment, however, that complicates the move:

"Thereupon Congress shall decide the issue, assembling within forty-eight hours for that purpose if not in session. If the Congress, within twenty-one days after receipt of the latter written declaration, or, if Congress is not in session, within twenty-one days after Congress is required to assemble, determines by two-thirds vote of both Houses that the President is unable to discharge the powers and duties of his office, the Vice President shall continue to discharge the same as Acting President; otherwise, the President shall resume the powers and duties of his office."

Essentially, that leaves the determination up to the Senate and House of Representatives.

In theory, yes, Mr Pence could have used the 25th amendment, but with so few days left in Trump's presidency, and with the need for congressional approval (highly unlikely with Republicans still in control of the Senate), such an effort would have almost certainly hit a wall.

Dr Peter Yacobucci, a political science professor at Buffalo State University, said the 25th amendment has been used in the past, but mainly for medical procedures where sitting presidents have had to be sedated.

"It has never been used to try and remove the power of a president against their will," Mr Yacobucci added.

Mr Yacobucci also said that although the 25th amendment sought to provide clarity, section 4 of the amendment actually makes things somewhat murky.

"This section also has a clause that states Congress can designate another body to make this determination," he said, making reference to exactly who gets to say whether or not the sitting president is able to perform his or her duties. "This is unchartered territory and nobody really knows that that means," he said.

As for whether or not the 25th amendment should be applied to Mr Trump, Mr Yacobucci did not skirt the issue.

"Yes, it certainly should be...since the election, President Trump's behavior has only gotten worse," he said. "The drafters of the Constitution never imagined a person so devoid of morals and character like President Trump would ever be president," he added.